Piston-casting.



1-. H. BAMBERG.

PISTON CASTING. APPLICATION FILED MAR. 1.. T917- v Patented Mar. 4, 1919.

2 SHEETS-SHEET I.

INVENTOR.

ATTORNEY.

I. H. BAMBERG.

1 PISTON CASTING.

APPLICATION FILED MAR. I. I9I7..

1,296,591. I I I I Patented Mar.4,1919.

2 SHEETS-SHEET Z- WITNESS:

'INVENTOR.

JOSEPH H. BAMBERG, or. TOLEDO, OHIO; nssrenon r0 THE ALuMINn'i/r GAS'IINGS COMPANY, or CLEVELAND, OHIO, A eomionnrron or 01-110.

igrs'roiv-onsrrne.

eeaaai.

Specification of Letters'latent.

Patented Mar. 4, 19190 Original application filed March 7, 1916, Serial No. 82,529. Divided and this application filed March 1,

' J 1917. Serial No. 151,777.

' To all whom it maytoncern:

Be it known that I, JOSEPH H. BAMBERG,

a citizen of the United States, residing at- Toledo, in the county ofLucas and State of Ohio, have invented certain new and useful Improvements in Piston-Castings, of which the following is a specification, reference be ing had therein to the accompanying drawmg. 1

This invention relates to an internal combustion motor piston casting having internally projecting bosses, webs, ribs and ex-' tensions, or either of them.

One object of my invention is to providea skirted piston cast of metal or metallic alloy of relatively low specific gravity and which is relatively non-porous, free from entrapped air and other gases and oxids and other foreign material's.

Another ob'ect' of my invention is to provide a skirted piston cast of metal or me-. tallic alloy of relatively low specific gravity and readily machinable to provide durable and efficient bearing surfaces. I

Another object of my invention is to provide a casting for a skirted piston for an internal combustion motor made from metal or metallic alloy of relatively low specific gravity and having diiferent structural characteristics at various sections as desired.

Another object of my invention is to provide a skirted piston casting-of metallic al- 10y having arelatively low specific gravity and a relatively high coeflicient of heat conductivity, which when machined and used in the cylinder of an internal combustion motor will not collect carbon to the same ex tent as does an iron piston and will take and retain a relatively high polish because of its fine-grained structure.

- Another object of this invention is to provide a skirted piston casting made of a mini-' mum volume 'of metallic alloy of relatively low specific gravity and high heat conductivity, which will not disintegrate nor undergo changes in its internal structure under ordinary usage in an internal combustion motor, and which will require a minimum amountof machining.

Another object of my invention is to provide a skirted piston castmg-made of a'me-' tallic alloy of relativelylow specific gravity and high heat conductivity and in which casting there is a relatively small amount of eutectic which substantially surrounds the excess substance in the casting.

Another object of my invention is to provide a skirted piston casting made of an alloy of relatively low specific gravity and high heat conductivity and in which casting there is a relatively small'amount of eutectic disposed relative to the excess substance in such manner as to provide efiicient and durable machined bearing surfaces.

Another object of this invention is to provide a piston casting of an alloy containing aluminum, copper and magnesium, having a structure relatively fine-grained, non-p0: rous and free from entrapped air and other gases and from oxids and other foreign materials. 7

Other objects of my invention will be ob-' vious to one skilled in the art from the description of it hereinafter made. A Y

The present application is a division of my pending application, Serial No. 82,529., filed March 7, 1916, in which I have fully set forth, and explained an. apparatus-and method suitable forthe production of the piston casting to which the present application relates. 1

In order that the present invention may be clearlyunderstood. I have shown in the accompanying drawings one form. of piston casting embodying my improvements and also a mold in which the casting is formed.

Figure 1 is a perspective view of a skirted -0r cup-shaped piston casting, after'the sprue has been removed. v

Fig. 2 is a central lon itudinal sectional view through the piston casting.

Fig. 3 is a central. longitudinal sectional view of the piston casting taken at right angles to the section shown in Fig. 2.

Fig. 4 is a bottom plan view of the piston casting. Fig. 5 is a side elevation of a mold adapted for the production of my improved piston casting, part of the view' being in section and the core pins being shown rembved.

Fig. 6 is a top plan view of the mold with the mold members separated and the casting attached to one of them.

wall 2 characteristic of the skirted pistons commonly employed in internal combustion I engines. The side wall is formed with diametrically opposite inwardly projecting bosses 3, 3 which are cored out to receive a wrist-pin, The upper part of the casting, as shown, is provided with strengthening and heat-dissipating ribs 4 and 5.

My improvements arenot limited to. the particular conformation of the casting shown but may be varied widely, as will be explanation of the matters which characterize my im-; provements.

The physical properties and interna.

" structural characteristics which chiefly charprises a base-member. a I members b and'o,

acterizemy invention are the result of the constituent materialsemployed in the casting and the manner in which the casting is formed. I will, accordingly, briefly describe I a mold designed for, the production of the casting and the manner in whichsuch mold is used. For a full description and explanation of the mold and the process of producingthe casting by means of it, reference is had to my pendingapplication, Serial N 0. 82,529, above referred to.

Referring to Figs. 5 and 6, the mold com I and complementary v -movable on the base member a toward and from each other. 03 indicates as an entirety'the main core part of the mold.- This core is fornied in a plurality of sections which are suitably recessed to .form the bosses 3, 3 and ribs 4: and 5 on the interior of the piston. 6,6 are diametrically opposite core pins arranged to project into the mold cavity to form openings in orthrough the bosses 3, 3 of the piston casting. These core pins are in.

the form ofrods which are slidably'mounted' in alining openings of the mold membersband'0.- 7

. The mold members 6 and 0 are formed with complementary cavities or' recesses 'b and c" which together form the mold gate.-

. i The gate thus 45' materially in the formed, as will be observed from Fig. 6, is disposed. midway between the internal bosses 3, 3 of the piston casting. As is fully explained in my'co'pending application referred to, I prefer to employ a gate constructed so that a liquid seal is formed which precludes the passage of air and gases into the. mold cavity and also reduces splashing of metal withgate during the pouring. Also the. gate is preferably-formed to communicate with the mold cavity at 'the bottom and at the: top of the cavity and at intermediate" points between the top and bottom.

The walls ofthe mold cavity are suitably coated'or treated, in any well-known man Irer, to reduce as much as possible agitation of the molten metal as it flows into contact d and e mayreadily be maintained at desired temperatures. As I have fully explained in my application, Serial-No. 82,529, the core pins are preferably-kept atr a temperature substantially lower than the other parts of the mold cavity walls, and the tem-' perature of the gate walls than the other parts of members 6 and c; and consequently whenthe molten metal, at a temperature hundreds of degrees above the temperatures of the mold walls, is poured into the mold cavity it is subjected to a very strong chilling action at points adj acent the core pins 6, e, and to a less marked but very substantialchilling action adjacent other parts of the cavity walls, while the higher temperature -of the gate walls insures the maintenance of molten metal'inthe gate until after freezing takes "place in the mold for heating is kept higher in fact, my co-pendhowever,

have peculiar advantages and adaptability for the production of castings to meet par ti'cular requirements, and the present application relates more especially to a piston casting formed of an aluminum alloy containing copper and magnesium. Whilethe proportions of these constituents may somewhat, Iprefer an alloyhavlng approximately the following composition: aluminum 91.75%, copper 8.0% and magnesium 0.25%. v

In making a, piston casting of metallic alloy such as last metal, at a suitable 1350" F. and 1400 through the mold. The ing the mold cavity fills the bottomthereof (this part of the cavity corres onding to the head of the piston)v and therea ter the molten temperature, between F., is poured by gravity gate and into the cavity of the referred to, the molten be varied first of themolten metal cntermetal, as it enters the. mold cavlt fi'lfi ws I a brief interval after the pouring has elapsed,

usuallyas soon as the crystallization shrinkage occurs, the core pins e, e are Withdrawn; and then after a suitable further interval the core d is removed, the mold members 6, c are separated and the casting removed.

The chilling efl'ect of the different arts of the cavity walls upon the metal of t e casting, when the casting is of a suitable composition and suitably poured in the manner.

referred to, gives to the casting" physical properties and internal structural characteristics which are remarkable and, as I- believe, greatly superior to any which have heretofore been obtained.

These superior properties and characteristics of my improved piston castings .are:

low specific gravity, high coeflicient of heat' conductivity, relatively great strength, and a non-porous fine grained structure free from impurities and from cavities due. to crystallization shrinkage and with the eutectic substantially surrounding the excess material in such manner as to provide a durable and efiicient bearing surface when the casting is machined. Furthermore the casting, with an internal structuresuch as described, has very excellent machining qualities, while, both because of its structural character and the accuracy with which it is formed, little machining is required in producing the'finished piston. Again the structure of the metal of the inner walls of the bosses 3, 3, resulting from the 'relativelvquicksetting of saidv metal, is particularly advantageous for cooperation with the wrist-pin.

By reason of its fine-grained, dense structure the casting, when machined, takes a high polish and has less tendency to collect carbon than does an iron piston.- I have mentioned the bearingand wearing qualities of the casting and, in that connection may add that I have been unable to note and disintegration in the structure of these castings after thousands of miles of severe'service 1n relatively high speed motors of the internal by the working temperaturesof the internal combustion motor to whichsaid castings are I substantially surrounds the excess substance subjected. 1 With respect to the relation of the eutectic and excess substance in my improved astings, I may observe thatjwhilethe eutectic as stated above, I believe it is desirable that itshould not entirely ,surround'and comproduce a relatively small quantity of eutcc-.

. having chilled. walls.

pletely isolate said excess substance; for, 'by

gest themselves, without departing from the spirit and scope thereof. My disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

What I claim is:

1. As a new article ofmanufacture, an internalcombustion motor piston casting made of an alloy consisting predominantly of aluminum and containing. copper and mag nesium, the castinghaving chilled walls and being fine grained and substantially free from porosity due to crystallization shrinka e. Y

2. As a new article of manufacture, an internal combustion motor piston casting made of an alloy consisting predominantly of aluminum and containing other elements such as copper and magnesium in proportions to tic in the casting after freezing, the casting having roundlng the excess substance therein and 3. As a new article of manufacture, an in- 'ternal combustion'motor piston casting made v of an alloy consisting predominantly of aluminum and containing other elements such as copper and magnesium in proportions to produce a relatively small quantity ofeutectic in the cas ing after freezing, the casting havin rounding the .excess substance therein and-- being fine grained and substantially free lot from porosity 'due to crystallization shrinkage.

as copper and magnesium in proportions to produce a relatively 'smallquantmy of eutectic in the casting after freezing, the'castmg having the said eutectic substantially sur 110 rounding the excess substance therein and being fine grained and substantially free from porosity due to crystallization shrinkage and entrapped air and other gases.

In testimony whereof, I hereunto aflix my 115 signature.

' .JosEPn H BAMBERG.

the said eutectic substantially sur- 7 the s id eutectic substantially sur- 4. Asa new article of manufacture, an internal 'combnstidn motor piston casting made of an alloy consisting predominantly of aluminum and containing other elements such 

